Conversion of hydrocarbons



Feb. 4, 1947.

Aw. L.. BENEDICTv Er AL 2,415,272

CONVERSION OF HYDROCRBONS Fileocf. 31, 1942 a/vley Patented Feb. 4, 1947CONVERSION F HYDROCARBONS Wayne L. Benedict and William J. Mattox,Chicago, Ill., assignors to Universal Oil Products Company, Chicago,Ill., a corporation of Dela- Ware 8 Claims.

matics.

The invention isV particularly applicable to a Application October 31,1942, Serial No. 464,082

processior the production of aviation gasoline and selectedmono-alkylated aromatics, such as toluene, ethylbenzene and the like.According to one embodiment of the invention, olefin-free alkylatedaromatic hydrocarbons may be produced. v

In one specic embodiment, the present invention comprises subjecting oilboiling'above the range of gasoline to cracking in the presence of acracking catalyst to produce a substantially saturated gasoline product,subjecting at least a portion of said gasoline to interaction withbenzene in the presence of a catalyst to effect a transfer of alkylgroups from poly-alkylated aromatics contained in said gasoline to saidbenzene, recovering a substantially saturated gasfline product suitablefor use in aviation fuel from VVthe rst step of the process, andrecovering selected mono-alkylated aromatic hydrocarbons from the secondstep of the process.

In another specic embodiment, the invention comprises subjecting oilboiling above the range of gasoline to cracking in the presence of acracking catalyst to produce a substantially saturated gasoline product,subjecting at least a portion of said gasoline to contact with acatalyst to eiTect saturation of the olenic hydrocarbons contained insaid gasoline. subiecting the olefinfree gasoline fractions tointeraction with benzene in the presence of a catalyst to eect atransfer of alkyl groups from the poly-alkylated aromatics contained insaid gasoline to said benzene, and recovering a substantially saturatedgasoline product suitable for use in aviation fuel from the first stenof the process. and recovering selected mono-alkylated aromatichydrocarbons whichare substantially olefin-free from the last stepyofthe process.

The particular conditions of operation to be employed in each step ofthe process Will depend primarily upon the charging stock to the rststep of the process which, in turn, will affect the materials to besupplied as charging stocks tothe subsequent steps of the process, andthe operating conditions will also depend upon the particular productsdesired. For example, if`1'noor fuel is desired, the rst step of theprocess may comprise a non-catalytic cracking operation or it maycomprise a catalytic operation in which the cracking is conducted underconditions to produce an olenic type of distillate. On the other hand,if a substantially saturated gasoline product is desired for use inaviation fuel, the first step of the process will comprise a catalyticstep in which the cracking is conducted under conditions to produce asubstantially saturated distillate. In any event, the distillate productwill contain varying percentages of aromatics, olens, naphthenes, andparains. If substantially olen-free toluene, ethylbenzene, etc., isdesired, the distillate from the rst step of the process is subjected tothe hydrogen transfer step prior to being subjected to the alkyltransfer step of the process. When the products from the cracking stepof the process have a sufciently low olefin content, the second step ofthe process may be omitted in cases where the nal alkylated aromaticproduct meets the desired specications as to olen content.

It is understood, of course, that the `various operations hereindisclosed are not necessarily equivalent in `their results and that theparticular choice will depend upon the considerations heretoforementioned.

The invention will be explained in detail in connection with theaccompanying diagrammatic flow drawing which illustrates several specicembodiments of the invention, although it is understood that Variousmodifications to the particular flow described may be made within thescope of the broad teachings of the present invention.

Referring to the drawing, the charging stock is introduced to theprocess through line I and is directed into cracking zone 2. Asheretofore described, the cracking operation will depend upon thecharging stock and upon the type of products desired, and thus crackingzone 2 may be of any suitable type of known cracking processes.Noncatalytic cracking operations are usuali-y conducted at temperatureswithin the range of from about 800 to about 1200 F. and under pressuresof from about atmospheric to 1000 pounds or more. Catalytic operationsare usually conducted at temperatures within the range of from abouttions.

500 to about 1200 F. or moreimd under .pressures of from aboutatmospheric to 1000 pounds or more. In catalytic operations the hourlyweight space velocity isusually within the range of from about .3 toabout 5. The hourly weight velocity as used herein is defined as the4weight of cil per hour per weight of catalyst in the reactor.

For non-catalytic operations the cracking zone usually comprises aheater, reaction chamber, ilash cha-mben' fractionating and condensingr. and an end 'boiling peint of between about 4to equipment. Forcatalytic operations the process may be either of a' fixed bed or movingbed type,

the latter being either of the iluidized type in which the hydrocarbonsmove at a faster rate within the reactor than does the catalyst, or ofthe slurry type in which a suspension of oil and scope ofthe presentinvention. The catalyst may be of either natural or syntheticorigin. Apar- `ticularly suitable catalyst is of the silica-alumina type 'andcomprises silica composited with alumina, zirconia and/or thoria, or thelike, and

'these catalysts may be `prepared in any suitable manner.

The products from zone 2 are directed through line 3 into separationzone l. Separation zone I may comprise one or a plurality -of suitableflashing, fractionating, distilling, absorbing and/or thereto may beseparated into the desired irac- Non-condensible gases may be removedfrom the upper portion of zone 4 and withdrawn from the process throughline 5 or allor a portion of these products may be returned by way oflines 6 and I to theA cracking zone. This type of operation isparticularly desired when the cracking is conducted in thepresencefof'hydrogen' or other' gases. Higher boiling residue maybe'withdrawn .from the lower portion of zone l through line 'l2 andremoved from the process. When desired.-

and particularly when the cracking is conducted in the presence ofcatalysts, all or a portion of the Aresidue may be returned by way oflines 8, 9, I0, and I to the cracking step for further conversiontherein. A lower boiling recycle oil, when Vdesired, may be separated inzone 4 and removed therefrom through line II and withdrawn from theprocess. Preferably, however, at least a portion' of this recycle oil isreturned by way of lines,4

and about 500 F. or more.

. All or a portion of the gasoline directed through line |.2.in themanner heretofore described is subjected to treatment in zone I3 in thepresence. of a suitable .catalyst and under controlled'conditions toeffect saturation of the olefins con. tained therein. This zone maylikewise assume any suitable-form and it may contain any suitablecatalyst. A particularly effective catalyst comprises silica compositedAwith alumina, zirf conia, and/or thoria, or the like, as heretofore-described in connection with the cracking step 'Y of the process.However, with these catalysts,

catalyst is passed to the heating and/or reaction the temperatureemployed in this step ofthe process is within the range of about 400 toabout 950 F. and preferably from about 4009to about 800 F. and usuallyat relatively low supelratmospheric pressures. The hourly'weight spacevelocity is within the'broad range of .3 to5. The

:reaction which occurs in the step of the process is one of hydrogentransfer;l that. is, the oleilns are saturated by the hydrogen liberatedfrom some of the other hydrocarbons in the reaction '.zone. However, it.is not intended to limit the in.

vention to this particular reaction since other reactions.- such asisomerization, cyclization, de' hydrogenation, etc. mayalso occur. Thecondi` tions in this step of the process, furthermore, are controlled sothat substantially no' cracking oc? curs, and thus `a. high recovery ofliquid products is obtained with 4substantially no gas formation. Theproducts from zone I 3 aredirected through line I5 into'separation zoneI6,.which zone may stripping zones whereby the products introducedcomprise one or more fractionatin'g, distilling, or other suitable zoneswhereby the productslintroj duced thereto may be separated intothe'desired fractions. Line I1 is provided for the removal of 9, I0, andI to the cracking zone for further conv version therein.

Depending upon the particular type of opera tion'selected, the gasolinefractions, which may or may not contain higher boiling material and thushave an end boiling pointof between about 400 and about 500 F. or more,may be withdrawn from zone! through line -I 2,- and in one embodif mento f the invention, are directed into hydrogen transfer zone I 3.. Whenit is desired to produce aviation gasoline, the material boiling withinIor slightly above the gasoline range may first be boiling point of.between about 250 and about 350 'In case an aviation gasoline 'cut` iswithdrawn any lighterproducts, although as heretofore'dek scribed, thelighter-products will in mostl cases v be of negllgiblelalnount and,whenvde'sired, line I1 `may be .omlttedg In one embodiment of ltheinvention, the products maybe separated. in .zone I6 into an aviationgasoline cut having van end boiling point within the range 'of fromabout 250.v to about 400 F.,fand this fraction may `jbe withdrawn fromthe process through line; I8. This operation is particularly` suitablewhenA an avi-- ation gasoline is nctwithdrawn through line I4 in themanner heretofore described, although it is within the scope oftheinvention to utilize the same even though theprior separation is made.In the latter case'it'may be desirable to blend the two streamswithdrawn from lines vI4 and III 'I'he remaining productsare withdrawn'from zone I 6 through line I9., In case it is not der' sired to separatean aviation gasoline cutin zone I8. the stream withdrawn' through linei9will contain the total products subjected to 'fr actionin zone. I3,either with or without light gases depending on whether line" I .1 isutilized.

through line I8, the stream withdrawn: through.

' line I9 will contain thehighe'rfboiling constitu *l ents. In anotherembodiment ofthe invention@ when desired'ythe total products from zoneI3V may'be'dl'rected through 1111'es"|5, 20, 2l and IS intoalkyltransferfzone 22. As' .heretofore men 'I transfer *zone .I'Ifmaybe'omitted vand the prode ucts withdrawn from zone I throughllne I2 niabe directed through unes v2| anais-to airy ferzonell.

, cient amounts to ehect a tr asesora the ch may undergode-poly-alkylation; that is, removal 'from the benzene'ring andde-polywf tion into two or more alkyl radicals, in which case thereshould preferably besumcient nzene present to accept the alkyl radicalsi.: ble* for transfer to-thebenzene. The benzene may be introduced tothe process through line 23 and is directed through line I8 into zone22.

Zone 22 may likewise be of any lsuitable form and may containanysuitable catalyst whereby to effect the transfer of alkyl groups fromthe poly-alkylated aromatic hydrocarbons to the benzene. A particularlysuitable catalyst comprises silica composited with alumina, 'zirconiaand/or thoria or the like, as heretofore described. The

footed at tempera catalyst in this instance, however, is preferably orsynthetic origin The reaction is usually efabout 800 to about i300 F.,andv preferably within the range of from about 1000 to abcut1200"` F.Likewise, relatively low Vsuperatmospheric pres suresare employed and inmost cases substantial-l es within the range of froml uw on the aromaticring are relatively lons.

ly atmospheric pressure is'utilized. y The hourly weight spacevelocities are yusually less than 5. Satisfactory hourly weight spacevvelocities are within the range of 0.5 to` 2. The exact conditionsoioperation to be employed in this step of the process will depend uponthe characteristics oi lthe material it into zone 22.

The products from zone 22 are directed through line 2t into separationzone 25. Likewise, zone it may comprise one or a plurality of flashing,iractionatins, distllling, absorbing and/or strip- -ping zones wherebythe products introduced thereto may be' separated into the desiredfractions. Light gases may be removed from the upper portion thereofthrough line 2t and may be withdrawn from the process or, when desired,these gases may be recycled to either zone 2 or zone 22 in any suitablemanner not illustrated.

The toluene fraction is withdrawn from zone 2t through line 2l.lEthylbenzene may be withdrawn sure of aboutl 5 pounds per square inchand at being directed through line l irom zone 20 through line 2s.Although not ilinstr-ated in .the dra =H s other selected slatedaromatics, such as isopropylbenzene, etc., may be sented from theproducts in zone 25 and with clrawn'thereirom in any suitable manner.When desired, a substantially aliphatic fraction may be separated fromtheproducts of zone 25 and withdrawn therefrom through line 29. All or aPortion oi? `this fraction is preferably recycled by way oi lines 30,it, and i to cracking zone 2 for `further conversion within the process.Higher within the scope of the present invention includes v semratlnyoneor more selectedmonohslkylated aromatico such as toluene,ethylbenaene, isoprog pylbenzene, butylbenzene, etc., from theproducts'- in zone l and removing the same by Away of line it. In this.particular operation hydrocarbons containing six or less carbon atomsto the molie-v culle may be removed from zone-6 through line t while theselected mono-alkylated aromatic may be removed therefrom through one ormore points such as line it. 'I his operation is particularlyadvantageous when 'asubstantially olefin-free al- Vinflated aromatic isproduced in the rst step i the process. In this operation the materialaromatic will be directed through line i2 either to zone l 3 orpreferably to zone 22 for conversion therein. f f

4 In still another 'modiilcaticn either one or more .selectedmono-alkylated aromatica may'be sepz -aratcdin zone' t and directedthrough line I2 to l hydrogen transfer reaction in zone Il to saturatethe oleilns and to subsequently withdraw an oleiinPfree alhlatedaromatic from zone I6 through line i8. In this operation the higherboiling material will be directed, by well known means not illustrated,to the alkyl transfer step of the process.

The following examples are introduced i'or the purpose cifurther-illustrating the invention but not with the intention of undulylimiting the same. i i

Examplel A Gulf coast ses ou having an A. P. r. gravity. of 30.2, aninitial boiling point oi' 426 F., andan This naphtha contained '18%aromatica and 3% olerlns, the rest being paramns and naphthenes.` Theremaining products of the cracking operation comprised incondensiblegases, recycle stock, cohaandloss. 'l

The above mentioned 300 to 400 F. naphthawas subjected to alkyl transferreaction by being mired with two volumes oi benzene and contacted with asilica-alumina catalyst ata temperature of l022 F. underatmospheric-pressure and at a space velocity of l for a one hour processcycle. 92.5% of liquid hydrocarbons were recovered. the uncondensedgases amounting to 4% and the carbon to 3.4% by'weight. 0I the liquidhydrocarbons recovered, toluene comprised 24.9 weight per cent ci? thecharge to thelsecond stop of the process. .iin ethylbenzene-xylenefractionwas recovered. which fraction comprised 28.3 weight per cent oithe naphtha charge to the second step of the process. Byrecycllng thehigher boiling alkillated aromatica to Ithe alkyl transferstep,additional yields of toluene, ethylbenzene and nylene may be obtained.

Example Il' A hydrocarbon fraction boiling within4 the range of 176 F.to 392 F. and comprising 72% aromatica and 23% oleiins was subjected totreatment with a silica-alumina catalyst at a temperature of 662 F; atAa. .space velocity of 0.5.

'No gas was formed and the hydrocarbon recovf g above the range-of themono-alkylated ered amounted to 95.3% by weight of the charge bonsboiling below 167 F., which amounted to 5 y 3% of this treated fraction,the aromatic concentrate contained no olefins. The above fraction may bemixed with two volumes of benzene and subjected to contact with asynthetically prepared silica-alumina cataly'stat a temperature 10 ofabout 1000 F. under atmospheric pressure and with a space velocity of 1to yield high concentrations of oleiin-free toluene and olefin-freeethylbenzene and xylenes.

vWe claim as our invention:

1. A, combination process for the production of gasoline and alkylaromatic hydrocarbons which comprises cracking a fresh hydrocarbon oiland an aliphatic recycle stock obtained as hereinafter described,separating from the resultant products a gasoline fraction having anend.Z point of from about 250 F. to about 350 F. and a naphtha fractionboiling above the range of said gasoline fraction and having an endpoint of from about 400 F. to about 500 F., said naphtha frac- 25 tioncontaining poly-alkylated benzene and 01e.- flns, converting olefinspresent in said naphtha fraction to more saturated hydrocarbons ands'eplarating a substantially olefin-free naphtha fraction, comminglingbenzene with said substantially olefin-free naphtha fraction andreacting said benzene -with poly-alkylated `benzene contained therein toeffect "the transfer of alkyl groups to said benzene, separating'vunconverted aliphatic hydrocarbons and a substantially` olen-freemono-alkylated benzene from the products of the last named'step,recovering said mono-alkylated benzene, and recycling said. aliphatichydrocarbons to the cracking step.

2. A combination process for the production of .40

gasoline and alkyl aromatic hydrocarbons which comprises cracking afresh hydrocarbon oil and an aliphatic recycle stock obtained ashereinafter described,"separating from the resultant prod' ucts afraction having an end point of from about 45.

400 F. to about 500 F., converting oleiins present in said last namedfraction to more saturated hydrocarbons, separating from the resultantprecincts a substantially saturated gasoline frac-l tion having an endpoint of from about 250 F. 50

alkylated benzene, commingling benzene with said naphtha fraction andreacting said benzene with poly-alkylated benzene contained therein toeffect the transfer of alkyl groups to` said benj zene, separatingunconverted aliphatic hydrocarbons and a substantially olefin-freemono-alkylated benzene from the products of the last named step,recovering said mono-alkylated benzene, and 1 recycling said aliphatichydrocarbons to the cracking step. g

3. The process of claim 1 wherein toluene is separated from the productsof the last stel-v 4. The processA of claim 1 wherein ethyl benzene isseparated from the products oi' the last step.

5. Theprocess of claim 1 wherein the cracking step is effected in thepresence of a silica-containing catalyst. 1

6. The process of claim 1 4wherein said reaction-of benzene withpoly-alkylated benzene is effected in the presence of asilica-containing catalyst.

7. The process of claim 1 wherein said step of converting olefinspresent in said naphtha fraction to more saturated hydrocarbons iseffected inl the presence of a silica-containing catalyst. n 8. Theprocess of claim 2 wherein said step of converting oleiinsy to moresaturated hydrocarbons is effected in the presence of a silica-con-`UNITED STATES PATENTS Number Country Date 2,242,960 Sachanen, et al. May20, 1941 2,234,984 .Sachanen, et a1. Mar. 18, 1941 2,290,211 Shaad July21, 1942 2,306,218 Marks Dec. 22, 1942 2,308,792 Thomas Jan. 19, 19432,335,596 Marschner Nov. 30, 1943' 2,343,870 Kaplan Mar. 14, 19442,349,834 Schmerling, et al. May/30, 1944 2,222,632 Sachanen, et a1.Nov. 26,1940 1,324,143 Brooks 4---- Dec. 9, 1919 2,010,948 Eglo Aug. 13,1935 2,010,949 Egloii. f Aug. 13, 1935 2,367,535 i Sowa Jan. 16, 19452,297,773 Kanhofer 1 Oct. 6, 1942` 2,283,854 Friedman, et al. May 19,1942 2,323,899

Day, et al. July 13,1943

